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Big sprite games.


Matej

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I was watching TRANTOR "demo". There is huge spaceship sprite at beginning and amazing big soldier sprite during text demo. Now I have this question. How many fonts can be used in one game (320kb,576kb,1088kb). Can we somehow use one charset for one level or screen??? To have huge sprites. Why we doesnt have lot of big sprites games??? There are few...

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As most of you probably know, the graphics in Trantor demo is taken from ZX Spectrum game (with the same title). But the guy's animation in this demo looks more like a slideshow (with switching between several prepared pictures) than a "proper" software sprite that could be used in a real A8 game.

Edited by +Adam+
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You can have as many character sets as you can fit into RAM, it's just a poke to select the one you want. As far as the giant space ship goes, I wouldn't have thought it was a sprite as such, just a block of redefined text scrolled into view so almost no CPU overhead.

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actually the spaceship movement in this demo is simply done by display list, and it doesn't take too much CPU cycles, it's simple scroller and can be done by mediocre programmer. The reason why we don't have big sprites in games is because it takes lots of CPU cycles to arrange bitplanes, in other words, when one have background and different sprites at the same time it takes a lot of CPU cycles to put one on another. Having 50 characters in character mode graphics that consist the software sprites is challenging. I think reasonable number of bitplane characters that can be animated in 1 frame is 30-40.

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The problem is - if you want to have good performance you have to store (in colour mode) 5x more data for every software sprite frame.

 

For example:

 

source data: object: 16x24 * 16 frames = 4x24 bytes * 16 frames = 1536 bytes

then all bit shifted animations to fonts = 1536 * 4 = 6144 bytes

 

~1.5kb + ~6kb just for one object

(if game wont dynamically allocate fonts we could drop the 1.5kb one)

 

edit:

Its not a problem if the game would use RAM extension of course.

Edited by solo/ng
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